Removes `base_path` argument when making the markdown extension for
parameters in documentation for API endpoints.
This seems to have been originally included for API parameters that
were documented in JSON files, which is no longer in use. Now all
API endpoints in the documentation are documented in
`zerver/openapi/zulip.yaml`.
Removes `base_path` argument when making the markdown extension for
return values in documentation for API endpoints.
This seems to have been a copy and paste error in commit d2ee99a2fd
when `zerver/lib/markdown/api_return_values_generator.py` was created.
Documents link to the bot's user card from the bot's name in
Organization settings > Bots, and information in the bot's user card.
Fixes part of #23970.
The max inline preview limit was previously increased to 10 by #20789.
However, as issue #23624 shows, it's still causing confusion for users
when they include more than 10 links.
Bump this limit up to 24, which is a multiple of the 4 image preview
per line logic.
Updates the help center article to match the style and formatting
of "Import from Slack" and replaces existing content with its
corresponding Markdown macro.
This uses the linkifier index among the list of linkifiers in the
replacement as the priority to order the replacement order for
patterns in the topic. This avoids having multiple overlapping matches
that each produce a link.
The linkifier with the lowest id will be prioritized when its pattern
overlaps with another. Linkifiers are prioritized over raw URLs.
Note that the same algorithm is used for local echoing and the
backend markdown processor.
Fixes#23715.
Signed-off-by: Zixuan James Li <p359101898@gmail.com>
The same pattern being matched multiple times in a topic cannot be
properly ordered using topic_name.find(match_text) and etc. when there
are multiple matches of the same pattern in the topic.
Signed-off-by: Zixuan James Li <p359101898@gmail.com>
Replaces instances of "recent topics" in the web-app and documentation
to be "recent conversations".
Renames both `recent-topics.md` files in the help center to be
`recent-conversations.md` and updates/redirects links to new URL.
Does not update instances of "recent topics" in frontend code comments
and does not update the main overview changelog, for now.
Does not change case study text where "recent topics" was referenced
in a quote, but does change generic text references to be "recent
conversations".
Adds new tab to `zerver/lib/markdown/tabbed_sections.py` to document
managing bots from both personal settings and organization settings.
Documents adding bots from the organization settings Bots panel.
Separates instructions for deactivating and reactivating a bot from
both personal settings and organization settings.
Fixes a few formatting issues such as missing bold formatting and
heading level.
Fixes: #23066.
9381a3bd45 added support for linkifier pattern URLs containing
`%20`-style escapes, but only did so for the codepath which is used in
the message body -- topic links did not understand them.
Expand the support to include when they are substituted into topics.
Due to mismatches between the URL parsers in Python and browsers, it
was possible to hoodwink rewrite_local_links_to_relative into
generating links that browsers would interpret as absolute.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Now the following characters are allowed before @-mentions and stream
references (starting with #) for proper rendering - {, [, /.
This commit makes the markdown rendering consistent with autocomplete
(anything that is autocompleted is also rendered properly).
`render_table` calls itself recursively when it finds nested
`additionalProperties` (i.e. nested objects) in response schema,
to render their properties.
This fixes `render_table` to call `render_desc` along with
calling itself, to render the description of the nested
`additionalProperties` as well.
This fixes inclusion of a multi-paragraph file into a list item.
Followup to commit dc33a0ae67 (#22315).
Signed-off-by: Anders Kaseorg <anders@zulip.com>
markdown-include is GPL licensed.
Also, rewrite it as a block processor, so that it works correctly
inside indented blocks.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Removes the ":" which have accidentally ended up in the "Get a link
to a specific topic" and "Get a link to a specific stream" headings.
Renames the "Via browser's address bar" tab to "Web" so that it
stays consistent with other help center articles.
Fixes part of #22147.
The `get_link_embed_data` / `link_embed_data_from_cache` pair as
introduced in c93f1d4eda uses the cache
as a temporary store inside of the `embed_links` worker; this means
that it must be durable storage, or the worker will stall and re-fetch
the same links to preview them.
Switch to plumbing through the fetched URL embed data as an parameter
to the Markdown evaluation which uses them, rather than using the
cache as an intermediary. This frees up the cache to be merely a
non-durable cache.
As a side-effect, this removes get_cache_with_key, and
link_embed_data_from_cache which was its only callsite.
Adds tab for web-public streams in documentation for setting
who can create new streams, as well as some text about why
this is limited to certain roles.
Removes list of actions that can be restricted to full members
due to maintainability concerns for that type of list in the
documentation and replaces it with a short descriptive text
explaining that many settings in Zulip support this restriction.
`prepare_linkifier_pattern`, as of db934be064, adds a match to the
end of the regex, of either the end of string, or a non-word character
-- this is in place of a negative look-ahead, which is no longer
possible in re2. This causes the regex to consume trailing
whitespace, and thus not be able to match twice in succession with
`pattern.finditer` -- "#1234#5678" fails to match because the space
is consumed by the first match of the regex.
Rather than use `pattern.finditer`, write own own version, which
rewinds over the non-word character consumed after the match, if any.
This allows the same "after" non-word character to also satisfy the
"before" of the next match.
Fixes#21502.
Extends the linking to Zulip documentation to cover:
- Getting URLs to messages via the message timestamp.
- Getting links to topics via the three-dots menu.
- Getting links to streams via right-click context menu.
Creates a new tabbed section for using the browser
address bar to copy URLs.
Adds documentation for admins to manage users via the user profile
modal for these actions:
- Deactivating a user
- Changing a user's role
- Changing a user's name
Creates two new tab sections because we still want to document
the ability to do these actions through the users section in
the organizational settings modal.
Also cleans up some text in the help center article for changing
a user's role.
Fixes#21318.
Fixes#21415.
Adds a check for `additionalProperties: true` when there are no
properties listed in the schema.
This currently only happens in one place, but will be helpful for
deduplicating text between the `register-queue` and `get-events`
endpoints.
Wordle has recently become a thing and it uses green, yellow and white (or
black in dark mode) large square unicode characters to let people share their
gameplay. Zulip converts the white and black large square unicode characters to
emojis, but not the green and yellow ones. This causes the Wordle grid to be
misaligned when shared on Zulip.
This commit adds green and yellow large square emojis to our emoji list to fix
the problem.
Fixes the rendering of enums to show strings with quotation marks,
while integers will continue to be rendered without quotation marks.
This allows for an empty string to be passed as an enum value and be
rendered as such in the documentation. Null will be rendered without
quotation marks, like integer values.
Formats and moves whether a field of an object in a request
parameter is required or optional to be in the same location
and have the same formatting as the general api parameter
documentation.
Also formats any examples within the object detailed
description to be the same as the general api parameter
documentation.
Follow up to #20409.
Adds a line break before the descriptive text for return
values and events in the api documentation in order to
help with readability of descriptions with multiple
paragraphs of descriptive text.
Adjustments made to the CSS of list items in unordered
lists to visually group the first paragraph of text
to any following paragraphs or unordered lists.
Adds a check for object in parameter type that will render the details
of the object in the parameter description if they are in the object
definition in the OpenAPI documentation.
Fixes#19424.
The limit here is purely to prevent breakage in case of a pathological
number of images in a single message; 5 images is entirely possible in
a reasonable message, and causes user confusion when they are not
expended.
Increase the limit to 10 per message.
This diff looks slightly noisy, but the main chunk of
code that we moved here has the same logic as before,
and it just gets realm_id from MentionBackend now, instead
of having our markdown processor have to supply it.
We basically want MentionData to be the gatekeeper of
mention data, and then we delegate backend tasks to
MentionBackend.
Soon we will add a cache to MentionBacked, which will
justify this change a bit more.
When our handlers specifically reference self.md.zulip_db_data,
we now use an explicit type.
We probably want a more robust solution here, such as a semgrep
rule.
We now serialize still_url as None for non-animated emojis,
instead of omitting the field. The webapp does proper checks
for falsiness here. The mobile app does not yet use the field
(to my knowledge).
We bump the API version here. More discussion here:
https://chat.zulip.org/#narrow/stream/378-api-design/topic/still_url/near/1302573
If null is a potential value of data type for a return value or
parameter in the API endpoint, then it is rendered as an option.
This currently relies on the 'nullable' setting in the OpenAPI spec
that was removed in the 3.1.0 release. If/when the OpenAPI version
is updated, then how the `data_type` for parameters and return values
is rendered will need to be reworked.
Fixes#20264.
Not proxying these requests through camo is a security concern.
Furthermore, on the desktop client, any embed image which is hosted on
a server with an expired or otherwise invalid certificate will trigger
a blocking modal window with no clear source and a confusing error
message; see zulip/zulip-desktop#1119.
Rewrite all `message_embed_image` URLs through camo, if it is enabled.
Supporting URL percent-encoded bytes is possible using `%%20`, but this
is not necessarily very understandable to end-users, even those that
understand percent encoding.
Allow `%20` in linkifier URL format strings, and transform them into
`%%20` in the pattern just before they are applied in markdown
translation. Care must be taken here, such that already-escaped `%`s
are not escaped an extra time.
We do this before rendering, and not before storage, as
a simplification; the JS-side linkifier at present only understands
`%(foo)s` and thus needs no changes, and to avoid an un-escaping pass
before showing in the admin UI.
og:image is supposed to be an absolute URL, but some sites incorrectly
provide a relative URL. In this case, it makes more sense to
interpret it relative to the full page URL after redirects, rather
than relative to just the domain part of the page URL before
redirects.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Zulip attempts to validate that the regular expressions that admins
enter for linkifiers are well-formatted, and only contain a specific
subset of regex grammar. The process of checking these
properties (via a regex!) can cause denial-of-service via
backtracking.
Furthermore, this validation itself does not prevent the creation of
linkifiers which themselves cause denial-of-service when they are
executed. As the validator accepts literally anything inside of a
`(?P<word>...)` block, any quadratic backtracking expression can be
hidden therein.
Switch user-provided linkifier patterns to be matched in the Markdown
processor by the `re2` library, which is guaranteed constant-time.
This somewhat limits the possible features of the regular
expression (notably, look-head and -behind, and back-references);
however, these features had never been advertised as working in the
context of linkifiers.
A migration removes any existing linkifiers which would not function
under re2, after printing them for posterity during the upgrade; they
are unlikely to be common, and are impossible to fix automatically.
The denial-of-service in the linkifier validator was discovered by
@erik-krogh and @yoff, as GHSL-2021-118.
This fixes the issue where 'None' would appear in the rendered
html in case of a missing tab display_name. Now,
'test-help-documentation' will fail in case of any tab display_name
being missing.
In case of a tab_section with no tabs, currently a single tab with
the name 'null_tab' gets added. Added the display name 'None' for
'null_tab', to keep in line with the existing behaviour.
Fixes#19822
Recently, we discovered that our settings_tab/relative Markdown
directives didn't work when they were in a macro that was included
in another Markdown file. Note that without this commit, the
/help/create-your-organization-profile page is broken. This commit
changes the respective priorities of these two extensions such that
these directives are rendered *after* the macro is included in
another file.
Thanks to Alya Abbott for reporting this bug!
All of our custom Markdown extensions have priorities that govern
the order in which the preprocessors will be run. It is more
convenient to have these all in one file so that you can easily
discern the order at first glance.
Thanks to Alya Abbott for reporting the bug that led to this
refactoring!
This check was copied from upstream python-markdown's "safe mode"
before they removed that feature. The upstream history is that they
introduced this check in
2db5d1c8e4,
which was not a complete security check, and then added the
immediately following check (with an allowlist of schemes) in
0b4ffbb60e.
Their first, incomplete check provides no security benefit and makes
the code hard to reason about, so we remove it.
This adds the X-Smokescreen-Role header to proxy connections, to track
usage from various codepaths, and enforces a timeout. Timeouts were
kept consistent with their previous values, or set to 5s if they had
none previously.
This commits removes some unnecessary checks for `self.md.zulip_message`,
which were put there historically, as earlier we used to add the additional
properties like mentions_user_ids, alert_words, etc. to Message dict
only. These were later moved to MessageRenderingResult class in commit
75cea329b but the checks weren't removed.
This is important because while rendering the messages imported from
other chat tools (like Rocket.Chat), the Message dict is not passed to
the markdown, due to which the checks for `self.md.zerver_message` fails
and hence, things like user mentions, stream/topic mentions are not
rendered in the imported messages properly.
These changes are all independent of each other; I just didn’t feel
like making dozens of commits for them.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
This way we can stop reading as soon as we get to the body. Also,
send an Accept header, check that the request was actually successful,
use lxml.etree.iterparse instead of a broken hand-rolled state
machine, and support XHTML, all for negative 28 lines of code.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
This reverts commit 1965584eec.
This syntax has a bad interaction with table syntax and needs to be
rethought.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
This is more efficient than get_lexer_by_name, since we don’t need to
instantiate the class just to get its name.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
The absence of __init__.py was preventing mypy from following any of
the zerver.openapi imports. These errors were being silenced by
ignore_missing_imports.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
As we have changed the tab selector above from "Settings" to "Personal
settings", we can simply change "Your bots" to "Bots" as "Bots" is
clear enough given the personal settings context.
We also need to update the API documentation for bots accordingly.
This commit fixes the documentation of settings as we have
replaced "Your account" section into two new sections -
"Profile" and "Account & privacy".
This commit also fixes a comment in the test for settings
documentation in test_middleware.py.
This adds a new class called MessageRenderingResult to contain the
additional properties we added to the Message object (like alert_words)
as well as the rendered content to ensure typesafe reference. No
behavioral change is made except changes in typing.
This is a preparatory change for adding django-stubs to the backend.
Related: #18777
Currently, the message that no parameters are accepted by
the endpoint is displayed if there are no parameters in
OpenAPI data, but it is possible that information is
encoded in x-parameter-description (example in upload-file
endpoint), and we want to display that information rather
than the message.
Added an if condition to check the same.
The headings for return values were currently hardcoded
in cases where they occur, but they can be rendered directly
in the markdown extension if the return values exist.
This should help with #17425, where messages with lots of LaTeX are
lost, due to the large expansion factor.
This isn't a total fix for this - large messages with lots of LaTeX
can still end up larger than 1MB, and rendering could timeout, but
this fix should help significantly.
1MB is still small enough that I don't expect we'll run into any DOS
problems - my testing didn't show any problems rendering messages that
contain ~1MB of LaTeX.
This will offer users who are self-hosting to adjust
this value. Moreover, this will help to reduce the
overall time taken to test `test_markdown.py` (since
this can be now overridden with `override_settings`
Django decorator).
This is done as a prep commit for #18641.
?dl=1 causes Dropbox to send Content-Type: application/binary, which
can’t be interpreted by Camo. Use ?raw=1 instead.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Prior to this, we only supported direct mention to
the user groups. This commit extends that support
to silent mention for the user groups.
A related test case is also added.
Fixes: #11711.
Earlier, USER_GROUP_MENTIONS_RE was:
r"(?<![^\s\'\"\(,:<])@(\*[^\*]+\*)"
For the syntax: *foo*, this was unnecessarily capturing it as
*foo* and the extraction of `foo` was done using another helper
function: `extract_user_group`.
This is now changed as:
r"(?<![^\s\'\"\(,:<])@(\*(?P<match>[^\*]+)\*)"
and extraction of `foo` can be done just by using the named capture
group `match`.
This change also helps to simplify its related code path.
Earlier, MENTIONS_RE was:
r"(?<![^\s\'\"\(,:<])@(?P<silent>_?)(?P<match>\*\*[^\*]+\*\*)"
For the syntax: **foo**, this was unnecessarily capturing it as
**foo** and adding extra operation for the extraction of `foo`.
This is now changed as:
r"(?<![^\s\'\"\(,:<])@(?P<silent>_?)(\*\*(?P<match>[^\*]+)\*\*)"
and extraction of `foo` can be done just by using the named capture
group `match`.
This change also helps to simplify its related code path.
Following the convention, we use uppercase for
regex. Also, `user_group_mentions` is given a
conventional name ending with `*_RE`: `USER_GROUP_MENTIONS_RE`.
Also link to it from the API documentation page,
other help pages, and the confirmation dialog for
muting a user.
With substantial edits by tabbott and alya.
A message containing wildcard mention when quoted (which
is turned into a silent mention) or message with silent
wildcard mention notifies the users by sending desktop,
sound, and missed message email notifications. This
is clearly a bug which is fixed by this commit.
Fixes: #18354.
* Move the extended documentation of code blocks to a separate page.
* Merge "code playgrounds" documentation to be a section of that page.
* Document copy widget on code blocks.
* This commit changes how we refer to "```python" type syntax for code
blocks. Instead of being called a syntax highlighting label, this is
now referred to as a "language tag", since it serves both syntax
highlighting and playgrounds.
* Remap all the links.
* Advertise this new page in various places that previously did not have a link.
Linked the Help Center document in places like
- zulip.yaml (/events, /register/, realm/playgrounds,
/realm/playgrounds/{playground_id})
- /help/format-your-message-using-markdown (Linked to make
users reading the markdown code block style, aware of this
feature)
- /templates/settings/playground_settings_admin.hbs (Linked
as a reference to read more about playgrounds before
configuring one)
Also showcase the feature on /features and /for/open-source.
Requesting external images is a privacy risk, so route all external
images through Camo.
Tweaked by tabbott for better test coverage, more comments, and to fix
bugs.
This logic likely never ran due to a combination of bugs.
* Running `maybe_update_markdown_engines` unconditionally meant that
`if md_engine_key in md_engines` was likely always true.
* Introduced in 65838bb: DEFAULT_MARKDOWN_KEY could never be in
md_engines, so should we have ever reached that code path, we'd have
tried to rebuild all markdown engines every time.
And it also wasn't clearly helpful -- because we fetch all linkifiers
for a realm on every request anyway, we don't really save database
queries by doing a bulk fetch on startup, and doing so would likely
result in a material regression to Zulip's overall startup time that
we were creating markdown engines for large numbers of realms in bulk
during process startup.
The comments explain in some detail, but basically we were displaying
the types for booleans incorrectly, and the types for strings in a
somewhat confusing fashion. Fix this with comments explaining the logic.
Using JSON dumping also results in our showing strings inside
quotation marks in our examples, which seems net helpful.
Thanks to ArunSankarKs for finding where we needed to change the
codebase.
Fixes#18021.
This reverts commit 9c6d8d9d81 (#16916).
This feature has known bugs, and also wants some design changes to
make it customizable like linkifiers, so we’re retargeting this to
post-4.x.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Backend logic for handling user mention was cluttered
because it was handled at two stages first in
get_possible_mentions_info while fetching mention data
based on the messsage and then later in UserMentionPattern
which handles processing of text for mention.
Ideally UserMentionPattern should depend on
get_possible_mentions_info only for data but there was a
shared logic between these two that made it hard to debug
any possible bugs.
Updates in this commit make both of these functions
coherent in terms of logic and also add appropiate
comments to improve readability of these functions.
There was also a hidden bug that if a user A is
mentioned in with @**name|id** then @**invalid|id**
again mentioned A because of the way we handled mentions
earlier. It is solved as a result of this refactor and
appropiate test has been added for this.
This has been tested manually as well as by adding new
test to address missing case.
Extend our markdown system to support mentioning of users
by id also. Following these changes, it would be possible
to mention users with @**|user_id** and silently mention
using @_**|user_id**.
Main intention for extending the mention syntax is to make
it convenient for bots to mention a users using their ids. It
is to be noted that previous syntax are also supported.
Documentation tweaked by tabbott for better readability.
The changes were tested manually in development server, and also
by adding some new backend and frontend tests.
Fixes: #17487.
We add support to shorten links and test their shortening in
well-organized, clean manner that makes it trivial to extend the
GitHub approach for GitLab and perhaps other services.
We only shorten basic types of GitHub links (issue, PR, commit) that
fit a set of simple common patterns; the default behaviour of Autolink
is kept for everything else.
Logic added in frontend and backend Markdown Processor is identical.
This makes easy to extend the logic for other services like GitLab.
Fixes#11895.
Modifies `StreamPattern` and `StreamTopicPattern` to inherit
from InlineProcessor instead of Pattern. This change is done
because Pattern stopped checking for matching patterns as soon
as it found a match which was not a valid stream. Due to this
all the subsequent mention failed, even if they were valid.
This bug was only present in backend renderring due to
markdown.inlinepatterns.Pattern.
Due to above changes verbose_compile is no longer used for
precompiling STREAM_LINK_REGEX, STREAM_TOPIC_LINK_REGEX as
adds ^(.*?) and (.*?)$ which cause extra overhead of matching
pattern which is not required. With new InlineProcessor these
extra patterns at beggining and end are not required.
So, StreamPattern and StreamTopicPattern now define their own
__init__ method for precompiling the regex.
Fixes#17535.
These changes were tested locally in dev server and by adding
some new markdown tests to test these.
Modifies `UserGroupMentionPattern` to inherit from InlineProcessor
instead of Pattern. This change is done because Pattern
stopped checking for matching patterns as soon as it found
a match which was not a valid user group. Due to this all
the subsequent user group mention failed, even if they were
valid. This bug was only present in backend renderring due to
markdown.inlinepatterns.Pattern.
This was reported as issue #17535.
These changes were tested locally in dev server and by adding
some new markdown tests to test these.
Modifies `UserMentionPattern` to inherit from InlineProcessor
instead of Pattern. This change is done because Pattern
stopped checking for matching patterns as soon as it found
a match which was not a valid user. Due to this all the
subsequent user mention failed. This bug was only present in
backend renderring due to markdown.inlinepatterns.Pattern.
This was reported as issue #17535.
These changes were tested locally in dev server and by adding
some new markdown tests to test these.
Currently, the ID and Type fields didn't have a description,
and weren't being displayed. Added a schema component to add
descriptions, and display on the api page. Fixes part of #15967.
Added assertion to check that if a deprecated flag is in a field's
schema, then it should have deprecated mentioned in description
as well, and moved these checks to a separate function.
Fixes part of #15967.
The current logic doesn't display data types when the additionalProperties
variables are not object, but are array of strings, etc. Changed the if
condition to allow rendering in such cases.
Previously, the data type of responses wasn't displayed in the API
Documentation, even though that OpenAPI data is carefully validated
against the implementation. Here we add a recursive function to
render the data types visibly in API Documentation.
Fixes part of #15967.
Commit 434094e599 (#11321) changed this
from an Extension to a subclass of Markdown, so it no longer has any
reason to use a config dict structured like that of an Extension.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
The changes are as follows:
• Fix one day offset in all western zones.
• Correct CST from -64800 to -21600 and CDT from -68400 to -18000.
• Disambiguate PST in favor of -28000 over +28000.
• Add GMT, UTC, WET, previously excluded for being at offset 0.
• Add ACDT, AEDT, AKST, MET, MSK, NST, NZDT, PKT, which the previous
code did not find.
• Remove numbered abbreviations -12, …, +14, which are unnecessary.
• Remove MSD and PKST, which are no longer used.
Hardcode the dict and verify it with a test, so that future
discrepancies won’t go silently unnoticed.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Previously, the data type of parameters wasn't displayed in the API
Documentation, even though that OpenAPI data is carefully validated
against the implementation. Here we add a recursive function to
render the data types visibly in the API documentation.
This only covers the request parameters; we'll want to do something
similar for response parameters in a follow-up PR.
Fixes part of #15967.
This reverts commit 564b199fe6, which
was part of #16308.
Escaping is either required or incorrect; it is never “defensive”.
This escaping is incorrect. lxml already escapes attributes during
serialization (any other behavior would be a serious bug), and
additional escaping just results in double escaping.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Initally, when writing two or more quotes, having
a blank line in between them, merges those quotes.
This created confusion especially in "quote and reply".
This commit fixes such issues. Now two or more quotes
having a blank line in between them, will not get merged.
This change is correct both for usability and for improving our
compatibility with CommonMark.
Fixes#14379.
See commit 8b002040e0 and #86. The
development environment bug that necessitated this handler has long
been irrelevant.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Initially markdown titles were overridden by Youtube and Vimeo preview titles.
But now it will check if any markdown title is present to replace Youtube or
Vimeo preview titles, if preview of linked websites is enabled.
Fixes#16100
Lauryn Menard
David Rosa
Anders Kaseorg
Trident Pancake
Zixuan James Li
Alya Abbott
Alex Vandiver
Mateusz Mandera
N-Shar-ma
Kartik Srivastava
Lauryn Menard
Tim Abbott
Puneeth Chaganti
Steve Howell
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